Broad Range Tuning of Phase Transition Property in VO₂ Through Metal‐Ceramic Nanocomposite Design

Abstract

Vanadium dioxide (VO 2 ) is a well-studied Mott-insulator because of the very abrupt physical property switching during its semiconductor-to-metal transition (SMT) around 341 K (68 °C). In this work, through novel oxide-metal nanocomposite designs (i.e., Au:VO 2 and Pt:VO 2 ), a very broad range of SMT temperature tuning from ≈323.5 to ≈366.7 K has been achieved by varying the metallic secondary phase in the nanocomposites (i.e., Au:VO 2 and Pt:VO 2 thin films, respectively). More surprisingly, the SMT T c can be further lowered to ≈301.8 K (near room temperature) by reducing the Au particle size from 11.7 to 1.7 nm. All the VO 2 nanocomposite thin films maintain superior phase transition performance, i.e., large transition amplitude, very sharp transition, and narrow width of thermal hysteresis. Correspondingly, a twofold variation of the complex dielectric function has been demonstrated in these metal-VO 2 nanocomposites. The wide range physical property tuning is attributed to the band structure reconstruction at the metal-VO 2 phase boundaries. This demonstration paved a novel approach for tuning the phase transition property of Mott-insulating materials to near room temperature transition, which is important for sensors, electrical switches, smart windows, and actuators.

Design of 3D Oxide–Metal Hybrid Metamaterial for Tailorable Light–Matter Interactions in Visible and Near‐Infrared Region

“…Furthermore, by properly selecting the metal nanopillar phase and oxide or nitride matrix, other novel functionalities such as tunable ferroelectric, ferromagnetic, and magnetoelectric coupling and thermal stability can also be enabled. [ 37–41 ]…”

An Artificial Mechano‐Nociceptor with Mott Transition

“…This behavior is generic in the case of Mott materials and reported previously. [23,[30][31] Since the main factors for the force-triggered Mott transition are the required force and tip diameter, finite element methods (FEM) analysis was performed to have a better understanding (see details in the Experimental Section). The simulated force distribution along the xz plane (z-direction of applied force) within the VO 2 material corresponding to two different tip diameters (e.g., 1 and 5 µm) under a fixed applied force (15 µn) is shown in Figure S5, Supporting Information.…”

Lithium-based vertically aligned nanocomposites for three-dimensional solid-state batteries

“…The OAD technique was applied to facilitate the metal pillar formation and to avoid the agglomeration of metal particles in the oxide matrix. [35][36][37][38] The Li The discontinuity observed in some of the Au pillars was attributed to the shadowing effect from the OAD growth. In this case, the small Au nanorods near the film-substrate interface are Au nucleates formed at the beginning stage of the growth that are shadowed by nearby taller pillars and stopped growing.…”

“…The OAD technique was applied to facilitate the metal pillar formation and to avoid the agglomeration of metal particles in the oxide matrix. [35][36][37][38] The Li 2 MnO 3 -Au VAN film was deposited from a single target containing both materials on Al 2 O 3 single crystalline substrates for structural analysis, as well as on stainless steel substrates buffered with Au for electrochemical measurements. The crystallographic analysis of the The discontinuity observed in some of the Au pillars was attributed to the shadowing effect from the OAD growth.…”